In a power generation system such as a thermal power plant using a large amount of fossil fuel, an amine absorption method is employed as a method of removing and recovering carbon dioxide that is one of causes of global warming. However, in the amine absorption method, thermal energy obtained from a great amount of steam having low pressure (for example, about 0.3 MPa) is required to regenerate an absorption liquid having absorbed carbon dioxide.
In order to compensate this thermal energy, there is proposed a method of joining condensate, which is branched from a turbine condensate system, to a deaerator after performing heat exchange between the amount of heat of recovered carbon dioxide and heat generated by compressing carbon dioxide to high pressure (for example, about 8 MPa) that is suitable for injecting carbon dioxide into the ground.
However, there has been a problem in that the amount of condensate is not enough to recover the total amount of heat of carbon dioxide. As a result, the amount of condensate flowing in a low-pressure heater is reduced and the amount of gas extracted from a turbine is reduced, so that the amount of heat dumped to a condenser is increased and the effect of a regeneration cycle in the related art is decreased. For this reason, there has been a problem in that the output of the turbine is not particularly increased by the amount of recovered heat.
Further, when recovered carbon dioxide is injected into the ground, it is necessary to compress carbon dioxide to high pressure. However, it was not possible to avoid the large reduction of the output of a power plant in order to secure a power source for this compression.